chore: use v3.1.0 contracts

Author: gzeoneth

test-node.bash

@@ -8,7 +8,7 @@ BLOCKSCOUT_VERSION=offchainlabs/blockscout:v1.1.0-0e716c8
 # nitro-contract workaround for testnode
 # 1. authorizing validator signer key since validator wallet is buggy
 #    - gas estimation sent from 0x0000 lead to balance and permission error
-DEFAULT_NITRO_CONTRACTS_VERSION="develop"
+DEFAULT_NITRO_CONTRACTS_VERSION="v3.1.0"
 DEFAULT_TOKEN_BRIDGE_VERSION="v1.2.2"
 
 # Set default versions if not overriden by provided env vars